Published: 04 October 2007
Helping Industry to respond to the Zero Carbon Challenge
Housing and Planning Minister Yvette Cooper has called on developers to refocus their efforts to deliver the eco homes of the future as Communities and Local Government published revised guidance to help the construction industry respond to the challenge of meeting the zero carbon homes target.
Currently the energy used to heat, light and run our homes account for 27% of all the UK's emissions.
The guidance, which responds to comments & feedback from industry, provides greater clarity in a number of areas including the future eligibility of different energy sources and the method for calculating anticipated water consumption.
The key changes are:
· The way energy efficiencies for flats with and without renewables are calculated
· The way water efficiencies are calculated, and
· The use of off-site renewable energy sources. In future, these will not be eligible unless directly connected to the development concerned. The Code continues to allow connection to gas and electricity grids as long as the home produces net zero carbon emissions over the year.
The Code Technical Guidance, including definition of zero carbon, will be kept under review as new evidence emerges about costs and practicalities, and as technologies develop.
Key features of a zero carbon development could include technologies such as:
Combined heat and power
Combined Heat and Power (CHP) is a fuel-efficient energy technology that, unlike conventional forms of power generation, puts to use the by-product heat that is normally wasted to the environment.
CHP can increase the overall efficiency of fuel use to more than 75%, compared with around 50% or less from conventional electricity generation.
District heating and cooling systems
District heating is a system for distributing heat generated in a centralized location for residential and/or commercial heating requirements.
District heating systems (DHS) distribute steam or hot water to multiple buildings. The heat can be provided from a variety of sources, including geothermal, CHP plants, waste heat from industry, and purpose-built heating plants.
Aquifer Thermal Energy
Aquifer thermal energy storage uses underground water reserves called aquifers.
There are two wells (typically) on either side with hydraulic coupling. One well is for the warm water and the other one is for the cold.
In the winter, warm water is cooled and passed to the cold well. Energy is extracted by a heat exchanger for heating purposes.
In summer, the process is reversed and cold water is used for cooling. Once heated, the water is stored in the cold well.
The advantage about this system is that it is environmentally safe; the water which circulates from underground to the heat exchangers and back can not be contaminated as it always remains in the system.
Ground Source Heat Pumps
Ground source heat pumps (GSHP) transfer heat from the ground into a building to provide space heating and, in some cases, to pre-heat domestic hot water.
Passive Heating
Passive heating systems are used in buildings which are insulated to a very high standard and make use of solar thermal gain and heat exchanges on ventilation systems, so that no external energy source (other than perhaps background heat generated by people living there and appliances) is required to keep the building warm.
Solar and Wind Energy
Solar energy can be used in a number of ways to provide energy. Passive solar energy is the use of sunlight to keep buildings warm through the direct warming effect of the sun on a building, eg via walls and glazing.
Thermal solar panels which provide space heating and hot water. Another method is to convert solar energy to electricity in photovoltaic cells.
Yvette Cooper said:
"We need to build more affordable homes but we also need to cut carbon emissions at the same time. That is why we are working with industry to meet the zero carbon challenge including through financial incentives.
"The ambition for all new homes to be zero carbon by 2016 is a challenging one. We need to work in close co-operation with housebuilders and the green technology industry to can achieve."
HM Treasury will shortly lay draft regulations before Parliament setting out definition of a zero carbon home for stamp duty land tax purposes.
An exemption on stamp duty land tax for new zero carbon homes was announced by the then Chancellor Gordon Brown last December.
Further information
Code for Sustainable Homes – Technical guide
Building a Greener Future: Towards Zero Carbon Development - Analysis Report of Consultation Responses
Related articles
Sustainable Construction Strategy
The Future has to be Green
The Carbon Challenge
Not just Selling, but also Saving
Working towards a Zero Carbon London
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